Wednesday, November 12, 2008

Oh The Struggle of Genes!

Two scientists, drawing on their own powers of observation and a creative reading of recent genetic findings, have published a sweeping theory of brain development that would change the way mental disorders like autism and schizophrenia are understood.

The theory emerged in part from thinking about events other than mutations that can change gene behavior. And it suggests entirely new avenues of research, which, even if they prove the theory to be flawed, are likely to provide new insights into the biology of mental disease.

At a time when the search for the genetic glitches behind brain disorders has become mired in uncertain and complex findings, the new idea provides psychiatry with perhaps its grandest working theory since Freud, and one that is grounded in work at the forefront of science. The two researchers — Bernard Crespi, a biologist at Simon Fraser University in Canada, and Christopher Badcock, a sociologist at the London School of Economics, who are both outsiders to the field of behavior genetics — have spelled out their theory in a series of recent journal articles.

"The reality, and I think both of the authors would agree, is that many of the details of their theory are going to be wrong; and it is, at this point, just a theory," said Dr. Matthew Belmonte, a neuroscientist at Cornell University. "But the idea is plausible. And it gives researchers a great opportunity for hypothesis generation, which I think can shake up the field in good ways."

Their idea is, in broad outline, straightforward. Dr. Crespi and Dr. Badcock propose that an evolutionary tug of war between genes from the father's sperm and the mother's egg can, in effect, tip brain development in one of two ways. A strong bias toward the father pushes a developing brain along the autistic spectrum, toward a fascination with objects, patterns, mechanical systems, at the expense of social development. A bias toward the mother moves the growing brain along what the researchers call the psychotic spectrum, toward hypersensitivity to mood, their own and others'. This, according to the theory, increases a child's risk of developing schizophrenia later on, as well as mood problems like bipolar disorder and depression.

What fun that outsiders can now make up theories about behavior genetics! I have one that has to do with the gender of all these researchers and the person who wrote the article as well as the kinds of terms selected here: "tug of war" between the sperm and the egg, indeed. I bet they are armed to their teeth, those eggs and sperm. Might it not be the case that these researchers started from their own gender war and worked inwards from that, hmh?

Then to the actual questions they pose which is really whether all these conditions are largely inherited from one parent (note that showing that for just autism doesn't prove their theory at all): There's a very simple way of getting some evidence on that. It's well known that the tendency towards schizophrenia has a genetic component. For instance, if both parents have it in their family lines the child is at a much higher risk. Now go back to those studies and find out if schizophrenia appears to be inheritable only in the female line or much more strongly through that. Then do the same for depression and bipolar disorder. Easy peasy.

But that's not what all this is about. It's about Simon Baron-Cohen's theory that people have male brains and female brains, the former being all systematic thinking and the latter being all emotions. Indeed, the article I link to specifically mentions his role as the starting-point of these theories. That Baron-Cohen is not an expert on genetics, either, doesn't matter for these boyz. That the test he offered for determining which kind of brain you might have is severely biased doesn't matter. That his book on all this ends with a fairly open scream of rage about the unfairness of this world to men doesn't matter. That he wrote two long chapters in it about his imaginations and dreams of the prehistoric society which created that systematizing male brain and that emotional female brain doesn't matter.

I'm not fighting against doing research of this kind or popularizing it, by the way. I'm fighting against the lower standards this kind of research is held to, and the language that is being used in the popularizations. Another example of that:

The theory leans heavily on the work of David Haig of Harvard. It was Dr. Haig who argued in the 1990s that pregnancy was in part a biological struggle for resources between the mother and unborn child. On one side, natural selection should favor mothers who limit the nutritional costs of pregnancy and have more offspring; on the other, it should also favor fathers whose offspring maximize the nutrients they receive during gestation, setting up a direct conflict.

The evidence that this struggle is being waged at the level of individual genes is accumulating, if mostly circumstantial. For example, the fetus inherits from both parents a gene called IGF2, which promotes growth. But too much growth taxes the mother, and in normal development her IGF2 gene is chemically marked, or "imprinted," and biologically silenced. If her gene is active, it causes a disorder of overgrowth, in which the fetus's birth weight swells, on average, to 50 percent above normal.

Here's the "struggle" again, between first the mother and the "unborn child" (hmmm), then between the mother and the father! The mother is all alone on one side. The fetus would love to grow humongous (except of course then it wouldn't get born at all and though it would win the war against its mother as she would die, so would the fetus)!

And this bit is very odd: " On one side, natural selection should favor mothers who limit the nutritional costs of pregnancy and have more offspring; on the other, it should also favor fathers whose offspring maximize the nutrients they receive during gestation, setting up a direct conflict." Why odd, you might ask? Because it assumes that once a baby is born it gets up and starts merrily procreating. A big and bouncy baby born out of a dead mother would have had a very tough time procreating, given that it might have died in the absence of breast milk and daily care. It's also odd because I usually read that argument in a slightly different format, that it's the men who want women to have pregnancy after pregnancy, to maximize the numbers of their own offspring, and that it's the women who want to limit the numbers of their pregnancies to stay alive a little longer.

In summary, note how this story is on the face of it a neutral discussion of some rather wild conjectures, but on the deeper level it sets women against men and mothers against both fathers and their own children.

So it's not really about autism and schizophrenia at all. But if we took the approach used in this popularization seriously we might then conclude that men seem to be doing well in this gender struggle as the rates of autism are rising.-----While looking for those Baron-Cohen links on my blog, I came across a post about Desmond Morris' new book, all about male superiority. What was very odd is that he, too, links to Baron-Cohen's idea that it's only men who collect things (supposed to be because they are systematizing). Bad research really does have staying power. Soon we shall all agree that it's men who collect things even though every yard sale and every flea market and every antique shop I visit has more women than men in them.

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